FINGER CLUBBING -- DIAGNOSIS

SCHAMROTH SIGN 

Absence of a closed triangular space described by the nails of two index 

fingers when their distal phalanges are held in dorsal opposition

PHALANGEAL DEPTH RATIO 

In normal fingers, the distal phalangeal depth should be smaller than the 

interphalangeal depth; this relationship is reversed in the finger with clubbing
.
Since calipers may not be readily available, physicians may estimate the 

phalangeal depth ratio